Electric valve rectifying system



Q PLAT/5 Vows 67?/0 VOL TS Harold W. Lord, b5 Mmm His Attornerg.

Patented Dec. 12, 1933 i' e,

y Harold 'WL' Lord,` Schencct adr,i General Electric Cmpanyf a ofA 'i Application l s claims. (ci. 17e-363i y MyT invention relates to 'electric'. valve" rectify-- ing systems andv more particularly to such systemsin whichY the average 'voltage o-the direct current circuit may bevariedv by controllingv the i conductivity of' anelectric valve. j Y

Heretofore there have been' proposed numerous rectifying' systems including electric-valves in which'the average Avoltage of`thedirect currentv circuit may' rbe controlled by controllingfthe conductvityjof the electric valves, as--for example, by utililninggrid controlledrgelectric valvesl and* applying tothe grids an` alternating poten-- tial variable" inI phase withV respe'ct'to the' anode potential ofthe valves,A orfby' varying the mag-- 16 ni-tude of a unidirectionalV ygrid potential, orv by any` other well" known means thus *delayingVv the f point in each-half'cycle-,of` positivev` anode vpoten-A tialat which a valve is made conductive.` It; has been found that, in electric valve -rectifying sys- `2`0- tems@comprisingr an' inductivey load circuit, the

act'eristicsofthe'frectifler'i's occasioned by" theV sudden` dropin thel anode voltage of a' noncom' dctive'electric valve` when thef other electricy valve becomes non-conducting.-

It is an-objectf of my invention; therefore,`

provide aniirnproved electricvalve rectlfyingi systemwhich will overcomev theV above mentioned'disadv'antages of thefarrangernent's "of the prioruart; which willbe sii'm'zylel and reliable in operation. Y "f Itis another object ofimyinventionfto provide anv improved: electric: valveirectifyingj system. in; which the averagezvolta'vge oi the-direct current circuitA mayv be;` uniformly controlled over the. entire range of operatiomj; i y

Itis a further;- object of my` invention to,A provide an. improved? electricA A, valve -rectifying .systemby means of, ;Which,;the average voltagef of. the direct current rcircuitmay. be controlled'and in which there are no discontinuities in the control/'characteristics 'oij'the apparatus. '1

In L accordance with` my'inventionan inductiver directcurrent lcradfcircuiti.isconnecte'ditobeerr ergized through I`a 'conventioxri'al" hill-,wave*recti-L and .the rectirying valves are provided'withcontrolgrids'by means of which the averagejvolttt'ger1 of tt'nrdirectY current circuit may 10ey controlled'1 inany weiiknown manner. Any inductitxivceiirfv the directicurrent circuit'` is shunt-' ed with resistsince; with` this arrangement it has" tliat,j` when current' has" been interrupted inoefof the ielectricvalves, the magneticfenergy" storedin the reactance maintains a' current* throug'h it` theY` parallel connected resistor thus niaintains a voltage acrossl this reactor topr'eventf a,` sudden-V drop in' thev anode potential of` the nonconductive electric valve lon the interruption of currentin theY other Fora oirmyinvention, i

togetherLVA andiiiirtherobjects thereofijrpereren'vcefisfacr tu tliefoiimmigV` description t taken inconnectiony with" theV accompanying drawing;V and; itsV scope" be pointedV outin tiieapperndedclainis; Fig; 1` ofthe drawing' illustrates diagrammaticaliy .one err'lbodlmentA of my inyentionfin which' the average potential ofy a" directeur-rent ladwircuitj is controlled' by applying# meneame vaivegnqs-an 4alternating potential variable in f while Figs.' t 2v and' 3,

operating characteristics oi thel apparatusiof '1`f to aid" in the understanding" n Reierring-fnowitbFig; 1`V of thel drawing, there is 1 illustrated' ,an "arrangement" for j transmitting energy anj'alternatingcurrent circuit 10 to a" directt'current load circuit' l`1.f This arrangement includes a'Y transformer' lzandl electric valves1'3iand1'4'connectedj'nla conventional mannerl tol otit'am; full wave rectification. Y Electric valvesj 13 arid-4` 14'l are eachp'rovided' with an anode, a cathode, and ai controlgrid and are preferabiv'oi'j the discontinuous'contr'ol type, the

"jeiammesof which' are vapor electric dischlngef'valves; B`y th'e term" discontinuous controlf-`electric valfve I vrefer to that 4type of valve jinfwhichithe starting 'ofcurrentin the 'valve isidetermmea by; me, potential Vupf-m its control ridbutin" whichV the current flowing {intlie @accanita interrupted: omsffibyY reducing its:

anode potential below the"critical"va1ue.- The'l ofthe'vaives 13 14"? are. connectedto their commonffcathod `circuiti through Qopposite halves orftlielsefonury; of'a grid :transformer l5; 'a'. current limiting resistor .16.' The grid` transformeilS mayf beenergiied "in snitabre mannerirorsecurmgth desiredexita: ticncrtne'gridofthe va1ve's13f`and14; although Ilhave byway4 o1' einau'npieL4 an" impedance What I claim as .new and desire to secure by Letters Patent of the United States, is:-

1. An electric valve rectifying system comprising a source of alternating current, a direct current load circuit, apair of discontinuous control electric valves interconnecting said circuits, means for rendering each of said valves conductive at an intermediate point in eachhalf cycle" of its positive anode potential, .a reactance device included in said load circuit formaintaining current in each valve for an interval after the alternating supply potential has reversed polarity, and means for producing a potential in said load circuit upon the interruption of current in eitherof said valves while the other valve is non-conductive to prevent a sudden decrease in anodey potential in said other valve.

2, An electric valve rectifying system comprising a source of alternating current, a direct current load circuit, a pair of discontinuous control electric valves interconnecting said circuits, a reactance device included in said load circuit, means for rendering each'oi said valves conductive at an intermediate point in each half cycle of its positive anode potential,l and means for minimizing discontinuities in the anode potential of each valve during its nonconductive periods comprising means for maintaining a potential across said reactance device during intervals when current is flowing in neither valve.

3. `An electric valve rectifying system comprising a source of alternating current, a direct current load circuit, a pair of grid controlled vapor electric discharge valves interconnecting said circuits, a reactance device included in said load circuit, means for impressing upon the grids of said valves alternating potentials retarded in phase with respect to their anode potentials, and

means for minimizing discontinuities in the` critical grid potentials of said valves comprising means for maintaining a potential across said -reactance device during kintervals when current is flowing in neither valve.

4. An electric valve rectifyingvsystem compris-- ing a source of alternating current, a direct cur-E rent load circuit, a pair of discontinuousl control electric valves, an inductive winding energized from said alternating current circuit and provided with an electrical midpoint connected to one side of said direct current circuit and with end terminals connected to the other side of said direct current circuit through said valves, a reactance device included in said load circuit, means for rendering each of said valves-conductive at an intermediate point in each half cycle of its positive anode potential, and means for preventing sudden decreases in the anode potential of either valve when the other valve becomes nonconducting comprising means for maintaining a potential across said reactance device during intervals when vcurrent is` flowing in neither valve.

5. An electric valve rectifying system comprising a source of alternating current, a direct currentload circuit, a pair of discontinuous control electric valves interconnecting said circuits, a reactance device included in said load circuit, means tervals when current is flowing in neither valve f comprising a resistor connected in parallel to 1 said device.

HAROLD W. LORD.V

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